<!DOCTYPE html>
<link rel="help" href="https://drafts.csswg.org/css-inline-3/#propdef-text-box-edge">
<link rel="help" href="https://drafts.csswg.org/css-inline-3/#propdef-text-box-trim">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<style>
@font-face {
  font-family: test-font;
  src: url(resources/cap-x-height.ttf);
}
.spacer {
  background: lightgray;
  block-size: 100px;
}
#target {
  font-family: test-font;
  font-size: 100px;
  line-height: 2;
  text-box-trim: both;
  text-box-edge: ex alphabetic;
}
</style>
<div id="container">
  <div class="spacer"></div>
  <div id="target">A</div>
  <div class="spacer"></div>
</div>
<script>
function run_tests(test_names) {
  const container = document.getElementById('container');
  const container_bounds = container.getBoundingClientRect();
  const target = document.getElementById('target');
  const target_bounds = target.getBoundingClientRect();

  // Test `getBoundingClientRect()` returns the trimmed box size.
  test(() => {
    assert_equals(target_bounds.top - container_bounds.top, 100);
  }, "getBoundingClientRect.top");
  test(() => {
    assert_equals(target_bounds.height, 20);
  }, "getBoundingClientRect.height");

  // Test `elementFromPoint()` hits `target` even if the point is above/below
  // the client rect, because the inner line box overflows the box.
  test(() => {
    const result = document.elementFromPoint(10, 90 + container_bounds.top);
    assert_equals(result, target);
  }, "elementFromPoint: 10px above the client rect");
  test(() => {
    const result = document.elementFromPoint(10, 130 + container_bounds.top);
    assert_equals(result, target);
  }, "elementFromPoint: 10px below the client rect");
}

setup({explicit_done: true});
document.fonts.ready.then(() => {
  run_tests();
  done();
});
</script>
